Pressure-relieving means for hydraulic calenders



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' 1,637,282 July 1927' c. SCHLATTER PRESSURE RELIEVING MEANS FOR HYDRAULIC CALBNDERS Filed March 16, 1927 5 Sheets-Sheet 5 :1: K %\\\\\\\\\\\\\\\\\\\w I Patented July 26, 1927.

UNITED. STATES PATENT OFFICE.

CARL SCHLATTER, OF WEBSTER, MASSACHUSETTS, ASSIGNOR TO S. SLATER &

SONS,

INCORPORATED, F WEBSTER, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

PRESSURE-RELIEVING MEANS FOR HYDRAULIC CALENDERS.

Application filed March 16, 1927. Serial No. 175,902.

This invention relates to a hydraulic calender for use in textile plants. The principal objects of the invention are to provide means for automatically relieving the pressure on the calender rolls when they are about to receive between them a zone of more than normal thickness or hardness in the cloth and at the same time to still supply enough pressure so that the cloth will eontinue to be driven frictionally and there will he no chance for it to stop or for the cylinders to suddenly grip the cloth and ruin it.

In the operation of machines for calendering heavy cloth, the bottom calender roll ordinarily is mounted to run evenly in its hearings and to be rotated by the friction of the cloth between it and the top roll which is positively driven. The bottom roll is subjected to hydraulic pressure of a sufficiently high degree to calender the cloth properly. Whenever two lengths of cloth are sewn together, the result would be the injury of the cloth if it were allowed to go through an ordinary pair of calender rolls. On the other hand, if the pressure were relieved from the bottom roll and this roll allowed to drop away from the upper one, it would of course no longer be rotated by friction and the cloth would stop. Then when brought back into contactwith the cloth. it would make a deep mark throughout the width of the roll. The cloth would receive an imprint from the hard spot which would be printed back on the cloth as projections at a distance apart equal to the circumference of the roll. As new operated. these calenders have to run merely during the passage of one cut of cloth and then have to be adjusted and another cut of cloth put in. on account of the above mentioned difficulties.

This invention is designed to relieve the lower roll so that it will not be. injured by the cloth as it goes through where sewed and yet allow it to continue to run under enough yielding pressure to carry the cloth through and keep the bottom roll running. Also the device is so arranged that it will continue to leave the bottom roll under its reduced pressure a longer or shorter time according to the distance along the goods in which the increased thickness occurs and then the pressure will be restored automatically. It is to be understood that the operation is automatic and takes place before the hard or thick spot enters the calender rolls and the full pressure 011 the rolls is restored as soon as such spot has passed between them. This action of course is designed'to permit of sewed lengths of fabric to pass through the calenders continuously but it will act in any case where a thick or hard portion is encountered in the fabric. Another important object of the invention is to avoid the breakage or damage of themachines by the passage through the rolls of any obstruction which may he in or on the cloth.

The invention involves other improvements in details of construction and combinations of parts as will appear.

Reference is to be had to the accompanying' drawings in which Fig. 1 is a perspective view of one end of a pair of calender rolls with a preferred embodiment of this invention applied thereto;

Fig. 2 is an endview on enlarged scale indicating the calender rolls and means for detecting the thick or hard spots in the cloth;

Fig. 3 is an elevation of the same with the calender rolls omitted and showing in sec tion the contact operated by the indicating device;

Fig. 4 is a plan of the same;

Fig. 5 is a side view of the solenoid for operating the controlling valves and its associated parts;

Fig. 6 is a sectional view of the control ling valves operated by the mechanism shown in Fig. 5;

Fig. 7 is a view of the piping;

Fig. 8 is a wiring diagram; and

Fig. 9 is a View similar to Fig. 2 showing a modification.

This invention is adapted to be applied to a calender comprising an upper roll 10 which is mounted in fixed bearings, and a lower roll 11 which is mounted in open top bean ings 12 carried at the top of a pair of hydraulic rams 13. Ordinarily the rams are supplied with water under pressure to hold the lower roll up against the upper roll, or rather the cloth passing between them, and the result is a practically rigid construction. If a piece of cloth goes through with a hard lump in it or the like, the rolls are forced to yield, and then they come back against each other with a hard blow which produces a Ill flat place on the roll and makes the cloth unsuitable for sale. On account of this detect it is impossible to sew cutsof cloth together end to end and put them continuously through the calender because the stitches furnish hard spots of this character, and the cloth is two thicknesses thick and the result is the injury ofthe goods.

This invention is designed therefore large 7 iv to permit of the sewing of cuts together end toend and putting, them through the calender continuously, thus avo ding the stoppage of the machine and the waste of time necessary in threading a new piece through for every Cllt OfClOfll. The inventiolr also. has other advantages as will appear. y

\Vith this invention the usual two rolls l0 and ll are not changed in any way, being mounted and operated in the usual manner. The elotlrispasscid through between them in the direction of the arrow in Fig. 2. Just before the cloth enters the rolls it is acted. upon by an indicating device which I have shown in the form of two rolls and 16. One of. these, rolls is mounted in s ationary hearings in blocks 17 at the sides of the machine and the other is mounted on a pair of levers 18 pivoted at 19 on-the blocks 1? and carrvingbearings for the roll 16. It will be obvious that whenthe cloth comes through withathickplace, as indicated at 20 where the two pieces of cloth overlap and are sewed togethenor any other hard or unyielding spot, the roll 16 will he raised thereby just before the-defect or scam enters the calender rolls.

One of these levers 18 is connected to an arm 21 which is adjustahly connected with a vertical rod 22 and secured in position by a pair of nuts or in any other desiredwvay. Thisrod 22 extends vertically down through a frame 23 mounted on the side of the frame Blot the machine. It connected with a plate 25 .which is' perforated to receive a guide pin 26 located in stationary position and is capable of moving up and down.

This )lat'eis )resseddown by. a 's )ring 27 l hearing at its top on the frame 23. This p ate is also provided with a connection 30. Theplate 25 is guided by rodsBE). I

The connection 30 iselectrically insulated from the plate 25' but has a metallic stud which. upon being raised. forms an electrical cqnlactwith a connection 31 adjustably carried by a vertical'rod which is mounted on'the angle 23 and is provided with a not for adj isting it;

It will be obvious; therefore, thatwhen the upper. roll L6 is raised it will act through I the mechanism just described and close the contact 30,31 and-complete a circuit from the mains to a solenoid 32. This solenoid has aplunger 33 which, on movingnp from the position shown in Fig. 5, changes the angular position of a lever 34 pivotally connected with it. This" lever 3% is 'iivoted at two points and 36, but both or them are floating pivots. They are .notitixecl in any stntionary position. The result of? this motion is to move upwardly a rod 3 connected with the pivot 35 and move downwardly a rod 38 connected with the pivot 36. The rods 37 and 38 are connected respectively with two valves 35) and 4.0. These valves cometo their seats when closed and ati'that time render the respective pivots 35 or 236 stationary tor the time being. Now in this case the valve 35) is raised and the valve 40 is closed. The valve 3!) is held closed yieldingly by a spring acting on the valve through a lever and link 52. The valve 1'0 is similarly held to its seat by a weaker spring 53 connected to a lever The water from the pump comes in to the two hydraulic rams from a pipe ll, through a passage 4-2 which has a seat at: the top for the valve 40, and through pipe -13 to the ram. Ordinarily the valve 39 is closed and the valve it) open. Now when the action just. described takes place, the valve 40 is closed and the alve 39 opened. This shuts oil the water from the pump to the hydraulic rams and allows water from the pipe 14 to enter past the valve 39 into the rains. This water is under low, and in fact yielding, pres ure, as will be apparent from the further description. The result is that the lower cylinder 11 is relieved tronrpositivo pressure under which it is normallv held and allowed to yield slightly, but for rrasonc-s which will now appear it cannot: drop away from contact with the cloth passimg through the calender, but will merely yield enough to allow the additional thickness or thehard spotto pass through and will then come back automatically under control of the pressure from the pump.

For this reason the lmvplcssure pipe llis connected with a cylinder 46 in which operates a single piston 45 connected with a heavy spring 47 under a head 48. The water entering the hydraulic ram through the pipe 4 is not under a constant pressure, but if resistance is met. the spring 47 will y eld and allow the pressure to drop a little, but not allow the roll to drop away from conta'etwith the upper roll and cloth, so that no imprint is made on the rolls and no flat place on the cloth. I

The cylinder 46 under the piston 45 is vented or drained through a port normally closed by a valve 55. The stem of this valve passes through aslot in the lever 54 and has nuts on it below. A spring 56 forces the valve up against its scat. \Vhcn the lever 5% is forced down at its outer end it pulls the valve down and vents the cylinder l6 and pipe 44;. Atoll other times no leakage takes place. This venting occurs when of calenders in which the lower roll 11 moves entirely out of contact with the upper roll 10 when the detecting device operates. As shown in Fig. 9 this requires the addition of a spring pressed roll (30 for continuously pressing the cloth against the roll 10, so that it will be advanced by the rolls 60 and 10 when the roll ll is out of contact.

Although I have illustrated and described only two forms of the invention I am aware of the fact that other modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore, I do not wish to be limited to all the details of construction herein shown and described, but what I do claim is 1. In a machine for calendering textile goods, the combination with a pair of calender rolls and hydraulic rams for pressing one roll toward the other, of a detector in advance of the rolls, a low pressure cylinder, a piston therein, yielding means for holding the piston in opposition to liquid in the cylinder, and means operated by said detector for controlling the flow of liquid from the hydraulic rams into saidcylinder, whereby when the liquid from the source of pressure is cut off, the rolls will be capable of yielding.

:2. In a machine for calendering textile goods, the combination with a pair of calender rolls. hydraulic rams at the ends of the rolls for pressing one roll toward the other with a high degree of pressure, and means for introducing a liquid under pressure into the two hydraulic rams and holding them under uniform pressure under normal conditions of operation, of a detector in advance of the rolls, a low pressure cylinder, a piston therein, yielding means for holding the piston in opposition to liquid in the cylinder, and means connected with said detector and controlled thereby for by-passing liquid from the hydraulic rams into said cylinder, whereby whenthe liquid from the source of pressure is cut off, the hydraulic rams will be under a lower degree of pressure.

3. In a machine for calendering textile goods, the combination with a pair of ca]- ender rolls. and a pair of hydraulic rams for forcing the rolls together, of a source of hydraulic pressure, means for conducting liquid under pressure from the source to the hydraulic rams, a cylinder having a piston therein, yielding means for resisting the motion of the piston. means for admitting liquid from the hydraulic rams behind the piston, and means located adjacent to the rolls for controlling the operation of the last named means to shut off the rams from the source of pressure and connect them with said cylinder when a thick or hard spot in the fabric is about to enter the rolls.

-l-. In a machine for calendering textile goods, the combination with a pair of calender rolls and a pair of hydraulic rams for forcing the rolls'together, of means for conducting liquid under pressure from a source of pressure to the hydraulic rams, a cylinder having a single acting piston therein, a spring for resisting the motion of the piston, means for admitting liquid from the hydraulic rams under the piston, means for controlling the operation of the last named means to shut off the rams from the source of pressure and connect them with said cylinder when thick or hard spot in the fabric is about to enter the rolls and means for venting said cylinder and allowingthe liquid to leak therefrom when the hard spot has passed and the normal connections are re stored.

5. In a machine for calendering cloth, the combination with a pair of calender rolls and hydraulic rams for operating them, of

a valve for cutting off the rams from their source of pressure, a movable member under which the fabric passes to the calender rolls, a solenoid connected with said valve for operating it, and means operated by the movable member for connecting up a circuit to energize the solenoid when said member moves.

6. In a machine for calendcring cloth, the combination with a pair of calender rolls and hydraulic rains for operating them, of a valve for cutting oil the rams from the source of pressure, a solenoid for operating the valve, a pair of rolls through which the fabric passes to the calender rolls, one of them being mounted to move when a hard or thick spot in the fabric passes between the pair, and means operated by the moving roll for connecting up a circuit; to energize the solenoid when the roll moves.

7. In a detecting device for a cloth calendering machine, the combination with a calender roll, of a pair of rolls located adjacent thereto for receiving the cloth between them, a pair of levers pivoted adjacent to the ends of one roll and having bearings therefor, whereby, when a hard or thick spot in the cloth passes between said rolls, saidroll will be moved and the levers will swing about their pivot, a rod connected with said levers to be operated thereby, an electric circuit having a contact adapted to be closed by the raising of said rod, a solenoid in said circuit, and means connected with the sole noid for cutting oil the pressure which holds the calender rolls together and immediately subjecting them to a lower degree of yielding pressure. i

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8. In a detecting device for a cloth calendering machine,the combination with a calender roll, of a pair of rolls located adjacent thereto for receiving the cloth between the'nnone of said rolls being mounted to turn on a stationary axis, a pair of levers pivoted adjacent to the ends of the other roll and having bearings for the other roll, a rod connected with said levers to be operated thereby, an electric circuit having a contact adapted to be closed by the raising oi. said rod, a solenoid in said circuit, and means connected with the solenoid for cutting oil the pressure which holds the calender rolls together and simultaneously subjecting thenrto a lower degree of yielding pressure.

9. In a calendering machine, the combination with the calender rolls and hydraulic rams for normally holding them together, of means lei-supplying the rams with water under pressure comprising; a pipe, a detector, a solenoid, means operated by the detector when a hard spot is about to pass between the calenderrolls for energizing the solenoid, a lever connected with the solenoid, two valves arranged to be operated by said lever, one of said valves being adapted to shut oil' the supply of pressure to the hydraulic rams and the other being adapted to connect the hydraulic rams with another pipc, a low pressure cylinder, said other pipe being connected with the low pressure cylinder, and yielding means for resisting the action of the water in the low pressure cylinder, the last-named pipe also being connected with the rams when the last-named alve is opened for subjecting them to the pressure in the low pressure cylinder.

10. In a device for subjecting a pair of calendcrrolls to a low pressure in an emergency, the combination with a. solenoid and means for energizing it when the emergency arises, of a lever connected with the solenoid, a pair of valves connected with the lever to be operated thereby, and so arranged that when the solenoid is energized, the first valve will be closed and the second valve will be opened, a valve block having two ports controlled by said valves, one port arranged to admit water under high pressure to the hydraulic rams of the calender couple, and the other port connecting the hydraulic rains with a low pressure cylinder, whereby when the solenoid is energized the rams will be cut oil from the high pres sure and connected with the low pressure, a low pressure cylinder connected with said block through the second valve and its port and having a piston therein, and a spring connected with said piston for resisting yieldingly the force of the water at the end of the piston, whereby the calender rolls will be subjected to a yielding pressure when the solenoid is operated.

11. In a device for subjecting a pair of calender rolls to a low pressure in an emergency,- the combination with a solenoid and means for energizing it when the emergency arises, of a lever connected with the solenoid, a pair of valves connected withthe lever to be operated thereby, and so arranged that when the solenoid is energized, the first valve will be closed and the second valve will be opened, a valve block having two ports controlled by said valves, one port admitting water under high pressure to the hydraulic rams of the calender couple, and the other port connecting the hydraulic rams with a low pressure cylinder. whereby when the solenoid is energized the rains will be cut oil from the high pressure and connected with the low pressure, a low pressure cylinder connected with said block through the second valve and its port and having a piston therein, a spring connected with said piston for resisting the force of the water at the end of the piston whereby the calender rolls will be subjcctcdto a yielding pressure when the solenoid is operated, a pair of levers connected with said valves, yielding means for moving said levers in a direction to close them, and means connected with the first valve for venting the low pressure cylinder when the first valve is open.

12. In a device for subjecting a pair of calender. rolls to a low pressure in an emergency, the combination with a solenoid and means for energizing it when the emergency arises, of a lever connected with thesolenoid, a pair of 'alves connected with the lever to be operated thereby, and so arranged that when the solenoid is energized, the first valve will be closed and the second valve will be opened, a valve block having two ports controlled by sald valves, one port admitting water under high pressure to the hydraulic rams of the calender couple, and the other port connecting the hydraulic rams with a low pressure cylinder, a low pressure cylinder connected with said block through the second valve and its port and having a piston therein, and means connected with the first valve for venting the low pressure cylinder when the lirst valve is open.

13. In a calendering machine, the combination with a pair of calender rolls and by draulie rams for forcing the rolls together, of a cylinder having a piston therein, means for admitting liquid from the hydraulic rams under the piston, means for controlling the operation of the last named means to shutoff the rams from the source of pressure and connect them with said cylinder when a thick or hard spot in the fabric is about to enter the rolls, and means for venting said cylinder and allowing the liquid to leak therefrom when the hard spot has passed and the normal connections are restored.

14. In a cal'endrin'g machine, the combination with a pair of calender rolls, and hy draulic rams for forcing the rolls together, of means for conducting liquid under pressure from a source of hydraulic pressure to the hydraulic rams, a cylinder having a piston therein, means for admitting liquid from the hydraulic rams behind the piston, and means located adjacent to the rolls for con- CARL SOHLATTER. 

